Replace deprecated pylint >=0.27 pragma with new form
Replace deprecated pylint >=0.27 pragma with new form

The disable-all pragma was deprecated in favour of the new skip-file
pragma in pylint >= 0.27. Since we're moving to 1.6.4, use this instead.

Signed-off-by: Brian Foley <a00e555871a6a538e97f8c44307104c884f8e869@google.com>
Reviewed-by: Federico Pareschi <ff862f58af48d157b995cd83870fbfa4aec8edf3@google.com>

yiannist/ganeti,ganeti/ganeti,mbakke/ganeti,andir/ganeti,ganeti/ganeti,yiannist/ganeti,ganeti/ganeti,mbakke/ganeti,andir/ganeti,onponomarev/ganeti,onponomarev/ganeti,yiannist/ganeti,mbakke/ganeti,andir/ganeti